Workpiece holders

ABSTRACT

A workpiece holder in which a body formed of resilient material has a plurality of workpiece engaging members, at least one of the members being connected to a free end portion of finger, with the finger being integrally connected to the body at the opposite end portion whereby the free end portion of the finger and the member connected thereto can flex relative to the body about its integrally connected end portion so as to be movable in inward and outward directions. Means are also provided to apply a force to said free end portion for moving it and the member in one of such directions while the resilience of the body material will effect movement of such components in the opposite direction.

United States Patent Sykes [45] Aug. 22, 1972 WORKPIECE HOLDERS2,082,345 6/1937 Lasser ..279/46 UX [72] Inventor; Alfred Ernest Sykes,329 Leicester 3,006,654 10/1961 Ben amin ..279/46 X Road, Markfield,England 3,123,433 12/1964 Ross ..279/123 UX 1,956,318 4/1934 Draper..279/106 X [22] Filed: April 23, 1970 PP .No.: 31,151 PrimaryExaminer-Francis S, Husar Attorney-Holman & Stern 301 ForeignApplication Priority Data [57] ABSTRACT April 29, 1969 Great Britain..21846/69 A workpie holder in which a body formed of resilient materialhas a plurality of workpiece engaging [52] US. Cl. ..279/4, 279/106,279/110 members, at least one of the members being com [51] 'f 31/101323b 31/18 B23) 31/30 nected to a free end portion of finger, with thefinger [58] Field of Search ..279/1 D, 4, 23, 41, 46, 50, beingintegrally connected to h b d at the opposite 279/ end portion wherebythe free end portion of the finger 56 R f and the member connectedthereto can flex relative to l 1 e erences the body about its integrallyconnected end portion so UNITED STATES PATENTS as to be movable ininward and outward directions; Means are also provided to apply a forceto said free D nd and member in one of 2,998,259 8/ 1961 Farnsworth..279/50 Such directions while the resilience f the body 2,994,5388/1961 Farnsworth ..279/50 material will. ff t movement f suchcomponents in 2,873,121 2/ 1959 Hahn ..279/1 D thopposite direction2,709,599 5/1955 Mann ..279/46 X 3,411,796 11/1968 Decker ..279/46 5Claims, 5 Drawing Figures PATENTED M1322 3.6 85. 844

sum 2 BF 5 INVENTOR P ATENTED 22 I973 3.685 844 SHEET 3 [IF 5 ,INVEQNTORATTQkNEYS PATENTEB AUG 2 2 I972 SHEET U [1F 5 PATENTEBAIJBZZ I9723.685.844

SHkU 5 OF 5 A'I'I lNi-iYb WORKPIECE HOLDERS This invention relates toworkpiece holders such as chucks and mandrels and has as its object theprovision of such a workpiece holder in an improved form.

In accordance with the invention, there is provided a workpiece holdercomprising a rotatable body of resilient material and having a pluralityof workpiece engaging members, a finger integrally connected at one endportion to the body and having an opposite free end portioncircumferentially spaced from the end portion connected to the body,said free end portion being provided with an integrally connectedradially extending tongue. One of said workpiece engaging members beingmounted on said tongue, a leaf portion integrally connected with thetongue at a location remote from the connection of the tongue with saidfree end portion, said leaf portion extending at substantially rightangles to the tongue and being integrally connected to the end portionof finger integrally connected to the body, with the leaf portionproviding lateral stability to its tongue, said free end portion, tongueand workpiece engaging member being adapted to flex relative to the bodyabout the integrally connected end portion of the finger for effectingmovement of the free end portion in generally radial directions withrespect to the axis of rotation of the body, and means operably relatedto the free end portion of the finger for applying a force to flex thefree end portion, tongue and workpiece engaging member in one radialdirection, the resilience of the material of the body and the fingercausing the free end portion, tongue, and workpiece engaging member, tomove in the other radial direction when the force is removed.

Preferably, a plurality of said fingers are provided and are connectedrespectively to the plurality of workpiece engaging members. The bodymay be in the form of a disc arranged so that when the workpieceengaging members are in their operative positions in which they engageand hold a workpiece, the latter will be disposed on one side of thedisc so as to project therefrom. Alternatively the body may be in theform of a tubular (preferably cylindrical) member and in this case theworkpiece when engaged and held by the workpiece engaging members wouldextend through the body.

Preferably, said means for applying a force to the finger or fingers isarranged to move the finger or fingers outwardly where the workpieceengaging members are adapted to engage the exterior of a workpiece andinwardly when said members are adapted to engage the interior of theworkpiece. Said means may be actuated manually or may comprise meanswhich may be mechanical, or hydraulic or pneumatic or of any otherconvenient form.

The invention will now be more particularly described with reference tothe accompanying drawings wherein FIG. 1 is an end view and FIG. 2 asectional side view (on the line 2-2 of FIG. 1) of one form of aworkpiece holder in accordance with the invention, FIG. 1 being shownwith a cover plate removed,

FIG. 3 is a sectional side view showing an alternative form of workpieceholder in accordance with the invention, and

FIGS. 4 and 5 are respectively a part-sectional side view and a sectionon the line 55 of FIG. 4 of another alternative construction ofworkpiece holder in accordance with the invention.

Referring firstly to the embodiment shown in FIGS. 1 and 2 a workpieceholder shown therein is in the form of a chuck having a body which is ofgenerally disclike form. As shown in FIG. 2 said body 10 is connected onone side to a cover plate 11 although said cover plate is removed fromthe view shown in FIG. 1.

- Furthermore the body 10 is formed of any convenient resilient materialsuch as an alloy steel.

There is also provided a plurality of workpiece holders 12 comprisingjaws which are adapted at their inner ends to engage and grip theexterior of a workpiece. Each workpiece engaging member or jaw 12 isadjustably mounted by means of two screws 13 which project through aslot 14 formed in the jaw and into threaded holes 15 formed in the body10. There are also provided a plurality of screwed adjustable stops 16for limiting the outward movement of each workpiece engaging member 12.

The chuck is provided with at least one and preferably as shown aplurality of fingers, there being depicted in the construction shown inFIGS. 1 and 2 three such fingers corresponding in number to the numberof workpiece engaging members 12. These fingers are indicated byreference numerals 17, 18 and 19. It is however to be understood (asmentioned above) that there may be only one of such fingers so that oneof the workpiece engaging members 12 would be mounted on the one fingerso as to be movable as hereinafter described, the remainder of theworkpiece engaging members then being fixed in use although they may beadjustably mounted as above-described.

In the embodiment shown in FIGS. 1 and 2 the three fingers 17, 18 and 19each have a free end portion indicated by reference numerals 17a, 18aand 19a respectively and each finger is integrally connected to the body10 at that end portion (indicated respectively by reference numerals17b, 18b and 19b) opposite to the free end portion. As will be seen fromFIG. 1 each finger is formed by cutting slots as indicated by referencenumerals 20, 21 and 22 through the thickness of the body 10. Furthermorethere is provided on each free end portion a radially inwardly extendingintegral tongue 23 on which the associated workpiece engaging member 12is mounted, each tongue being defined between further slots 24 and 25which are each of right angle form so that at their inner ends theydefine therebetween a leaf portion 26 which is integrally connected tothe associated tongue 23 at a position remote from the connectionbetween the tongue and the free end portion. Each of said leaf portions26 provides lateral stability to its integral tongue 23.

As above described it will be appreciated that since the body 10 isformed of resilient material the free end portions of the fingers 17, 18and 19 together with their tongues will be able to flex about theirintegrally connected end portions 17b, 18b and 19b so that they can moveinwardly and outwardly relative to the central axis of the body 10.

For the purpose of moving said fingers 17, 18 and 19 in an outwarddirection there is provided fluid pressure actuated means in the form ofa cylinder 27 and a piston 28. The piston 28 is of annular formsealingly engaged with said cylinder and connected on one side to acollar 29 which in turn is connected to the three arms 30 of a togglemechanism, the inner end of each arm being connected by a bearing to thecollar 29 while the outer end of each arm 30 is connected by a similarbearing to an abutment formed, in the fingers 17, 18 and 19. At aplurality of positions around the periphery 'ofthe chuck, namely in abacking plate 31 connected to that side of the body 10 opposite to thecover plate 11 are inlet valves 32 and there is also provided an arcuatepressure box 33 containing an arcuate piston 34 in which is formed aslot 35 communicating at its inner end with a groove 36'.-The chord ofthe body 10 which is spanned by the pressure box 33 is at least equal tothe chordal distance between any two of the inlet valves 32 so that withthe pressure box stationary and the body 1 rotating said body can bestopped in any position and once stopped will always have at least oneof the inlet valves 32 in communication with the groove 36 and slot 35in the piston 34. Thus pressurized air can be admitted to the pressurebox 33 via a connection 37 and such pressurized air will first of allforce'the piston 34 inwardly to form a seal onto the backing plate 31when the chuck has been stopped. The pressurized air.

will then pass the appropriate inlet valve 32 and into the cylinder 27to move the piston 28 from left to right as seen in FIG. 2 sostraightening the toggle mechanism 30 and thereby pushing each of thefree end portions of the fingers 17, 18 and 19 outwardly. This in turnwill move the associated workpiece engaging members 12 outwardly as welland thereby permit the insertion or removal of a workpiece from betweenthe inner ends of said members 12. The valves 32 are relatively loosefitting so that when the pressure is removed from the pressure box 33pressurized air can escape around said valves from the cylinder 27 andsince the free end portions of. the fingers l7, l8 and 19 will have beenstressed in being moved outwardly by said toggle mechanism theresilience of said material forming the fingers and the body will causethe fingers to move radially inwardly and thereby enable the inner endsof ried-by the tongue of the free end portions are gripping a workpiecethey will be sufficiently flexed so that they grip the workpiece by theresilience of the material forming said fingers and the body 10, whereaswhen it is required to release the workpiece the fingers will be furtherstressed by operating the piston 28 and toggle mechanism 30 to move thefree end portions outwardly. It will also be appreciated that thefingers in their movement between a release position and a grippingposition will move in a plane parallel to the plane of the body 10 sothat the inner ends of said workpiece engaging members 12 will be able.to obtain a secure grip over the whole length of a cylindrical orparallel sided workpiece.

In the alternative embodiment shown in FIG. 3 the chuck depicted thereinhas a plurality of jaws 38 which are adapted to engage the interior of ahollow workpiece shown in dotted lines by reference numeral 39. There isalso provided a plurality of fingers 40 which may be formed in a mannergenerally similar to that described with reference to FIGS. 1 and 2 andthere is also provided fluid pressure actuated means for moving thefingers. In this case however said fluid pressure actuated meanscomprises a cylinder 41 and a piston 42 and a connection is made to thecylinder 41 via a central aperture 43 through which pressurized air canpass into the cylinder. Each of the fingers 40 (only one of such fingersis indicated in FIG. 3) is connected via a pin 44 to a flexible link 45which is made up of a plurality of strips of flexible material and theinner end of each link 45 is secured to a further pin 46 and heldbetween two parts 47 and'48 connected to the piston 42. Thus movement ofthe piston 42 from left to right as shown in FIG. 3 will result in theinner end of each link 45 moving in a direction parallel to the axis ofthe piston thereby causing the outer end of each link to be movedinwardly. This in turn will move inwardly the associated finger 40 andwill similarly move the jaws. 38 inwardly closer towards each other soas to release the component 39. When the air pressure in the cylindercomponent 39 or another similar. component loaded into position.

Referring now to the construction shown in FIGS. 4,

and 5 this construction comprises a chuck of generally tubularcylindrical form, there being an outer stationary part 49 and an innertubular body 50 which is connected at one end to a pulley 51 therebysaid body 50 can be rotated relative to the stationary part 49 onbearings 52 and 53. On each side of the median diametral plane of thebody 50 there is provided a plu rality of fingers 54 which are eachformed by cutting a U-shaped slot through the thickness of the wall ofsaid body 50 so that each finger is free at one end 540 and isintegrally connected at its other end 54b to the remainder of the body,the body being made of a resilient material such as an alloy steel asbefore. There v are thus provided two sets of fingers at opposite axialends of the body and the fingers of one set are aligned with the fingersof the other set looking in an axial direction. Each axially alignedpair of fingers 54 is interconnected by an axially extending pin 55which as shown in FIG. 4 extends at each end into a bush 56 fitted tothe adjacent finger and-intermediate its ends the pin 55 extends througha bore formed in an arm 57. As will also be seen from FIG. 4 there is aclearance indicated by reference numeral 58 between that part of the pin55 intermediate its ends and the body and also between the body and saidam 57. Intermediate its ends each arm 57 is mounted on a fulcrum pin 59mounted in the body and at that end of each arm opposite to the pin 55is a roller 60 carried by a suitable further piston 65 and non-returnvalves 66 and 67 are provided adjacent to ports 68 and 69 for thepurpose of admitting pressurized fluid to one end or the other of thecylinder 64. All of the circumferentially spaced cylinders 64 andassociated pistons 63 and 65 operate in the same manner so thatdescription of one such assembly will suffice.

Thus looking at FIG. 4 if pressurized fluid is admitted via ports 68past the non-return valve 66 into the righthand end of the cylinder 64the two pistons 63 and 65 will be moved to the left and the tapered ring61 will also be moved to the left. Said tapered ring will then engagethe rollers 60 on the arms 57 and this will have the effect of pivotingsaid arms about their pivot pins 59 so that the pins 55 are movedradially outwardly. Said pins 55 in turn will move the fingers 54radially outwardly and therefore release any component previously heldby the fingers and extending through the tubular body 50. A newcomponent can then be inserted into the tubular body 50 and pressurizedfluid admitted to the left hand end of the cylinder 64 as seen in FIG. 4via the port 69 while pressure is released from the right-hand end ofsaid cylinder 64. This in turn will move the tapered ring 61 from leftto right as seen in FIG. 4 and the fingers 54 will then be able to moveradially inwardly under the resilience of their connection to theremainder of the tubular body 50 so as to exert a resilient grip on thenew component placed in the chuck. It is of course understood that withthe tapered ring 61 in its right-hand position as shown in FIG. 4 thefingers 54 would naturally move radially inwardly to a position which issomewhat nearer to the axis of the tubular body 50 in the absence of acomponent in said tubular body. If the component is therefore inposition it will be gripped by inward radial contraction of the freeends of the fingers 54 when the tapered ring 61 is moved from left toright. As is the case with the construction described in FIGS. 1 and 2however the free end of each finger 54 will move in a plane parallel toa diametral plane of the body 50 so that a firm and secure grip can beobtained over a finite axial length of a component inserted into thechuck.

In the above-described construction, the free ends of the fingersthemselves act as the workpiece engaging members or jaws althoughseparately formed jaws may be attached to said fingers instead.Furthermore in an alternative construction a generally tubular chuck asshown in FIGS. 4 and 5 may have only one movable finger (which may havean attached or integrally formed jaw) and this movable finger wouldco-act with a plurality of fixed jaws.

In the construction shown in FIGS. 1 and 2 as an alternative to thetoggle mechanism 30 for actuating the fingers, a hydraulically actuatedthrust pad may be placed in each of the slots 21, each pad beingexpandable by hydraulic pressure to move the fingers outwardly whendesired.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

l. A workpiece holder comprising a rotatable body of resilient materialand having a plurality of workpiece engaging members, a fingerintegrally connected at one end portion to the body and having anopposite free end portion circumferentially spaced from the end portionconnected to the bod said free end rtion bein provided with an integraly connected ra lally exten ing tongue, one of said workpiece engagingmembers i being mounted on said tongue, a leaf portion integrallyconnected to said tongue at a location remote from the connection of thetongue to said free end portion, said leaf portion extending at rightangles to the tongue and being integrally connected to the end portionof the finger connected to the body, with said tongue providing lateralstability to its tongue, said free end portion, tongue and workpieceengaging member being adapted to flex relative to the body about the endportion of the finger integrally connected to the body for effectingmovement of the free end portion, tongue and workpiece engaging memberin generally radial directions with respect to the axis of rotation ofthe body, and means operably related to the free end portion forapplying a force to flex said free end portion, tongue and workpieceengaging member in one radial direction, the resilience of the materialof said body and the finger causing the free end portion, tongue andworkpiece engaging member to move in the other radial direction when theforce is removed.

2. The workpiece holder as claimed in claim 1, in which saidforce-applying means includes a togglemechanism and fluid-pressure meansoperably coupled with the toggle-mechanism for actuating thetogglemechanism.

3. The workpiece holder as claimed in claim 2 in which saidtoggle-mechanism includes toggle links of flexible form.

4. The workpiece holder as claimed in claim 2 in which saidfluid-pressure actuated toggle-mechanism comprises a piston andcylinder, said body having a plurality of radially extending,circumferentially spaced ports, each having a non-return valve foradmitting pressurized fluid to the cylinder, a stationary arcuatepressure box and an arcuate piston mounted within the pressure boxprovided on the exterior of the body, said pressure box extending overan arcuate distance at least equal to the arcuate spacing between anytwo adjacent ports, and said arcuate piston being adapted to besealingly engaged with the exterior of the body when the body isstationary and having passage means for admitting pressurized fluid fromthe pressure box to at least one of the ports when the toggle-mechanismis to be actuated.

5. A workpiece holder as claimed in claim 1 in which said free endportion, tongue and leaf portion are all defined by slots provided insaid body.

1. A workpiece holder comprising a rotatable body of resilient materialand having a plurality of workpiece engaging members, a fingerintegrally connected at one end portion to the body and having anopposite free end portion circumferentially spaced from the end portionconnected to the body, said free end portion being provided with anintegrally connected radially extending tongue, one of said workpieceengaging members being mounted on said tongue, a leaf portion integrallyconnected to said tongue at a location remote from the connection of thetongue to said free end portion, said leaf portion extending at rightangles to the tongue and being integrally connected to the end portionof the finger connected to the body, with said tongue providing lateralstability to its tongue, said free end portion, tongue and workpieceengaging member being adapted to flex relative to the body about the endportion of the finger integrally connected to the body for effectingmovement of the free end portion, tongue and workpiece engaging memberin generally radial directions with respect to the axis of rotation ofthe body, and means operably related to the free end portion forapplying a force to flex said free end portion, tongue and workpieceengaging member in one radial direction, the resilience of the materialof said body and the finger causing the free end portion, tongue andworkpiece engaging member to move in the other radial direction when theforce is removed.
 2. The workpiece holder as claimed in claim 1, inwhich said force-applying means includes a toggle-mechanism andfluid-pressure means operably coupled with the toggle-mechanism foractuating the toggle-mechanism.
 3. The workpiece holder as claimed inclaim 2 in which said toggle-mechanism includes toggle links of flexibleform.
 4. The workpiece holder as claimed in claim 2 in which saidfluid-pressure actuated toggle-mechanism comprises a piston andcylinder, said body having a plurality of radially extending,circumferentially spaced ports, each haviNg a non-return valve foradmitting pressurized fluid to the cylinder, a stationary arcuatepressure box and an arcuate piston mounted within the pressure boxprovided on the exterior of the body, said pressure box extending overan arcuate distance at least equal to the arcuate spacing between anytwo adjacent ports, and said arcuate piston being adapted to besealingly engaged with the exterior of the body when the body isstationary and having passage means for admitting pressurized fluid fromthe pressure box to at least one of the ports when the toggle-mechanismis to be actuated.
 5. A workpiece holder as claimed in claim 1 in whichsaid free end portion, tongue and leaf portion are all defined by slotsprovided in said body.